Vitamin D – more important than calcium for bones?

Vitamin D is one of the most important vitamins that our body needs. Whilst Calcium is best-known for its bone supporting function, it is Vitamin D that plays just as an important role in enhancing the absorption of calcium and phosphorus. Despite its importance, vitamin D deficiency is unfortunately very common, particularly within the UK population. This is mainly due to our lack of sunlight exposure (which is our main source of vitamin D) along with a low intake through the diet. Food sources of vitamin D include oily fish, such as salmon, mackerel and sardines, eggs and raw milk. However, due to the increase of fish and poultry farming, vitamin D levels in these sources are lower than expected. For example, farmed salmon was found to have approximately 75% less vitamin D in comparison to wild salmon. Other factors which further contribute towards low vitamin D levels include old age, pregnancy and breastfeeding, dark or covered skin, sunscreen use, obesity and the intake of certain medications such as metformin.
As we are now approaching winter where our exposure to sunlight will be very limited, it is important to ensure that our vitamin D levels are kept within optimum levels. This is particularly important as vitamin D can support various infections and it is also supportive of mental health conditions such as Seasonal Affected Disorder) SAD) and depression.
Recent recommendations have advised that everyone in the UK should supplement with 400 iu of vitamin D during autumn and winter, and all year round for those with limited sunlight exposure even during summer such as those who cover up for religious reasons or individuals with an indoor, sedentary lifestyle e.g. working in an office. Where there is a deficiency, individuals will require significantly larger doses of vitamin D of around 2000-4000 IU administered for at least 3 months and levels then retested. I use Vitamin D3 and K2 drops (D3 is more absorbable) for enhanced bone health.